Hammer drill



c. A. SHlNN 2,484,471

HAMMER DRILL 2 Sheets-Sheet l Filed Dec. 26, 1947 INVENTOR.

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Oct. 11, 1949. c. A. SHINN 2,484,471

HAMMER DRILL Filed Dec. 26, 1947 2 Sheets-Sheet 2 4. IN V EN TOR.

Patented Oct. 11, 1949 UNITED STATES PATENT OFFICE HAMMER DRILL Charles A. Shinn, Cbeltenham, Pa.

Application December 28, 1947, Serial No. 794,009

2 Claim. (CI. 74-22) This invention relates to hammer drills.

An object of the invention is the .provision of hammer drills which may. be converted readily into an ordinary drill by releasing a pin to permit a cam to revolve simultaneously with a positively driven cam, the first-mentioned cam when retained against rotation by the pin causing reciprocation of the second cam when the irregular face of the driven cam is revolved against a complementation face of the releasably retained cam for imparting a sliding motion to a bit.

A further object of the invention is the provision of a hammer drill that may be converted into an ordinary drill by releasing a member having a cam face acting against a complementary cam face on a second member fixed to a driven shaft, said coacting cam faces causing reciprocation of the shaft and a bit-equipped chuck, means being employed for releasably retaining the first-mentioned member against rotation, said shaft being revolved by a gear fixed on the shaft and slidably in mesh with a gear driven by a motor.

The invention consists in the novel construction, arrangement and combinations of parts hereinafter more particularly described and claimed.

In the drawings:

Figure 1 is a fragmentary front view in elevation of a convertible hammer drill,

Figure 2 is a longitudinal vertical section of the hammer drill taken along the line 2--2 of Figure 1,

Figure 3 is a horizontal transverse section taken along the line 3-3 of Figure 1,

Figure 4 is a fragmentary vertical section showing the arrangement of a pair of cooperating cams on a driven shaft,

Figure 5 is a fragmentary rear view showing the arrangement of the cams, operating gear and a bearing for the inner end of a driving shaft.

Figure 6 is a view in elevation of a combined gear and cam in detached relation, and

Figure 7 is a view in elevation of a cam cooperating with the cam shown in Figure 6 for producing a reciprocatory motion of the drill bit.

Referring more particularly to the drawings l designates a casing suitable for housing the various instrumentalities of the device. Said casing includes a passage for a bearing I l at the reduced front end and a passage at the outer end for a bearing l2. Said bearings are fitted neatly into their respective passages.

A driven shaft I3 is received by the bearings II and I2 and has a coupling means or chuck l4 which supports a bit l at the outer end of said shaft. The inner end of the shaft carries a thrust bearing l6 abutting the inner end of a Journal box IT for the bearing sleeve l2. Said journal box is formed integrally with the casing.

A gear 26 has an integrally formed sleeve 2| which is pinned at 22 to the shaft ii. A driving gear 22 is revolved by a shaft 24 that in turn is rotated by a motor (not shown) mounted in the easing II. The gear 20 is slidabl in mesh with the gear 22.

A bearing 26 has a tight-fit within a cam sleeve 26. The bearing however, is loosely received by the shaft II. The sleeve 2| has a cam face 21 (Figure 6) adapted to contact a cam face 26 (Figure 7) on the end of the sleeve 26. A coil spring 29 on the shaft l3 and disposed between the front wall lid of the housing and the gear 26 forces the shaft inwardly so that the cam faces will always be in contact with each other. Each of these faces have high points or curved ribs 21a and interfitting alternately disposed depressions 28a.

A plunger 36 having a. manipulating knob 3| is slidably mounted in a passage 32 formed in an offset portion 33 of the casing Ill. This offset has a passage 34' at right angles to the passage 33 and opening into said passage. A detent 35 at the inner end of the passage 34 is pressed into one of the notches 36 or 31 by a spring 38 held in place by a set screw 39. The plunger 30 has a reduced end to provide a pin 40 received by a pocket 4| in the sleeve 26.

The operation of my device is as follows: When the device is employed as a hammer drill the plunger is forced inwardly until the end 46 is seated in the pocket 4| of the sleeve 26 whereby the sleeve and its cam face 28 will be maintained stationary. The detent seated 1n the notch 36 will retain the plunger in this posltlOll. Rota tion of the shaft will cause the face 21 on the sleeve 2| to revolve on the cam face 26 thereby forcing the shaft to move outwardly against the tension of the spring 29 when the high points of the cam faces are in contact. The spring will return the shaft inwardly when the high points on the cam faces mesh with the complemental depression in the faces.

If it be desired to operate the device as an ordinary drill the plunger 30 is pulled outwardly. The sleeve 26 will then rotate with the sleeve 2| and the shaft. The spring will exert sufficient pressure on the sleeve 2| and shaft l3 to maintain the sleeves 2| and 26 temporarily in clamped relation. The plunger 30 at this time retained in position by the detent 66 which is seated in the pocket 31.

3 What I claim:

1. A hammer drill adapted to be converted into an ordinary drill comprising a casinl. a shaft mounted for rotation and reciprocation in the casing. coupling means on one end of said shaft for carrying a tool, means for revolving the shaft. a sleeve slidably mounted on the other end of the shaft and provided with a cam at one end,

a second sleeve secured on the shaft intermediin the opposite direction while the spring alternately returns said shaft, and means releasing the connecting means between the first sleeve and the casing to cause the sleeves to revolve in synchronlsm. '7

2. A hammer drill adapted to be converted into an ordinary drill comprising a casing, a. shaft mounted for rotation and reciprocation in the casing, coupling means on one end of said shaft for carrying a tool means for revolving the shaft. a sleeve slidably mounted on the other end of the shaft and provided with a cam at one end. a second sleeve secured on the shaft intermediate said coupling means and said first sleeve and having a cam at one end adapted to be engaged by the cam on the first sleeve, a spring urging the shaft in one direction for retaining thecams in engagement, the first sleeve having a pocket, I, plunger slidably mounted in a passage in the easing and provided with a pin received by the pocket for retaining said sleeve against rotation so that when the shaitis rotated the second-mentioned cam will ride over the first-mentioned cam and -move the shaft longitudinally in the opposite direction while the spring alternately returns said shaft, and means for manually releasing the plunger to cause the sleeves to revolve in synchronism.

CHARLES A. BHINN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS DemonetQ. Sept. 12, mos 

